1. Field of the Invention
This invention is directed to a structural building panel as well as a standing seam, metal roofing product or panel, in general, and to such a panel that weather proofs the structure that it covers and also is a structural component attached to the structure and protects the attaching hardware from weather, in particular.
2. Prior Art
A standing seam roof is typically a roofing system that attaches to the structure in a non-positive way as not to create a positive bond to the building. This roof is considered to be “floating” and is not used in the calculations to determine shear values of a structure. This roof system is designed to waterproof the structure only.
Another metal roof panel is a bat and seam roof which has a cap which covers the vulnerable seam preventing moisture from entering the structure. This roof panel is another “floating” roof using a clip to hold down the panel. This system has no shear strength value. This system is designed to waterproof only.
Other roofing systems which screw through the roof panel do not have weather protection from the attaching hardware or have not been designed with a standing seam construction so as a structural panel.
In all instances, the lack of shear ratings in “floating” roof panels requires extra framing under the roof to accommodate the lack of strength and integrity that the typical metal roof does not offer.
The screw down panel systems do create a certain amount of shear value but leave the attaching hardware vulnerable to the weather and is not a standing seam roof.
It has long been desired to obtain a joint for standard (not specially preformed) roofing sheets of so-called corrugated or V-crimp type. Such sheets are used extensively as shipped from the factories in closely nested packs and carried in stock by dealers of such materials in all parts of the country. In use they are almost invariably overlapped and nailed down, the nails being driven through the high ridges (high parts of the corrugations or crimps) on the theory that water will not seek an opening at the top of such exposed ridges, but will run off into the low areas. This, however, has proven a fallacy, inasmuch as the nails are exposed and work loose whereupon water penetrates the roof. This roof is merely a sheet metal panel and is not considered a standing seam roof. Various methods have been proposed to overcome this defect, but most of them require working of the standard sheets in the field and often requires special tools which increases the insulation costs.
Other methods of panel manufacture have been advocated which require the manufacturer to make a special sheet with obvious manufacturing, distribution and application drawbacks. However, even with such special sheets, exposed nails are still involved, and the surfacing does not prevent the access of water. On these panels the attaching hardware, either screws or nails, is exposed directly to the weather.